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3 years ago

What are two ways that scientists can study Earth's climate history?

Chemistry

2 answers:

Inessa [10]3 years ago

6 0

Records and previous occurrings

k0ka [10]3 years ago

5 0

places and things are eroded.
helller

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The molar volume of a certain solid is 142.0 cm3 mol−1 at 1.00 atm and 427.15 k, its melting temperature. the molar volume of th

kotykmax [81]

Answer:

$\Delta _{fus}H=3255.3J/mol$

$\Delta _{fus}S=7.62\frac{J}{mol*K}$

Explanation:

Hello,

Clausius Clapeyron equation is suitable in this case, since it allows us to relate the P,T,V behavior along the described melting process and the associated energy change. Such equation is:

$\frac{dp}{dT}=\frac{\Delta _{fus}H}{T\Delta _{fus}V}$

As both the enthalpy and volume do not change with neither the temperature nor the pressure for melting processes, its integration turns out:

$p_2-p_1=\frac{\Delta _{fus}H}{\Delta _{fus}V}ln(\frac{T_2}{T_1} )$

Solving for the enthalpy of fusion we obtain:

$\Delta _{fus}H=\frac{(p_2-p_1)(V_2-V1)}{ln(\frac{T_2}{T_1})} =\frac{(11.84atm-1.00 atm)(156.6cm^3/mol-142.0cm^3/mol)}{ln(\frac{429.26K}{427.15K} )} \\\\\Delta _{fus}H=32127.3atm*cm^3/mol*\frac{101325Pa}{1atm}*(\frac{1m}{100cm} )^3\\\Delta _{fus}H=3255.3J/mol$

Finally the entropy of fusion is given by:

$\Delta _{fus}S=\frac{\Delta _{fus}H}{T_1} =\frac{3255.3J/mol}{427.15K}\\ \\\Delta _{fus}S=7.62\frac{J}{mol*K}$

Best regards.

5 0

3 years ago

Substance X is a compound containing 632mg of manganese and 368mg of oxygen. Substance X is shown

defon

The empirical formula : MnO₂.

<h3>Further explanation</h3>

Given

632mg of manganese(Mn) = 0.632 g

368mg of oxygen(O) = 0.368 g

M Mn = 55

M O = 16

Required

The empirical formula

Solution

You didn't include the pictures, but the steps for finding the empirical formula are generally the same

Find mol(mass : atomic mass)

Mn : 0.632 : 55 = 0.0115

O : 0.368 : 16 =0.023

Divide by the smallest mol(Mn=0.0115)

Mn : O =

$\tt \dfrac{0.0115}{0.0115}\div \dfrac{0.023}{0.0115}=1\div 2$

The empirical formula : MnO₂

8 0

3 years ago

How do you find what the reaction symbols are of the compounds in a chemical reaction?

user100 [1]

When you know the number of moles in either the reactant or product and also when the compounds involved are either basic or acidic

3 0

3 years ago

if the density of water is 1 g/ml, what would happen to an object with a mass of 80 g and a volume of 100 cubic cm when you plac

Nastasia [14]

Answer:

that object will float on the water

Explanation:

Since the density of water is greater than that of the object , the object will float on the water.

NB. Density of the object=

$\frac{mass}{volume}$

Given that mass of the object is 80g and volume 100cm^3

substituting them in the formula

Density=80g/100cm^3

Density=0.8g/cm^3

since 0.8<1 which is the density of the object and water respectively, the object will float.

5 0

3 years ago

How many liters of water must be added to 5.40 g of sodium nitrate to create a solution that has a concentration of 3.81 g/l? us

Yakvenalex [24]

the concentration has been given as g/L. this is the mass of solute that can be dissolved in 1 L solution.
the concentration of the solution that needs to be prepared - 3.81 g/L
the mass of sodium nitrate is - 5.40 g
the volume needed for 3.18 g - 1 L
then the volume needed for 5.40 g - 1/3.18 x 5.40
volume of water needed - 1.42 L

3 0

3 years ago

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